<!DOCTYPE html>
<html lang="en" ng-app="myModule">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="js/angular-1.3.0.js"></script>
</head>
<body>
<div ng-controller="test">
    <span>{{span_show()}}</span>
</div>
<script type="text/javascript">
    var myModule = angular.module("myModule",[]);
    myModule.controller("test",["$scope",function($scope){
        $scope.str = "first string...";
        $scope.span_show = function () {
            $scope.str = "reset string...";
            return $scope.str;
        };
    }]);
</script>
</body>
</html>